The Nonlinear Deformation of the Body System Under Electromagnetic Field Action

The paper discusses issues concerning the deformation of a system of conductive bodies under the action of the electromagnetic field. Problem of nonlinear deformation of technological system for electromagnetic forming is considered as a practical application. The problem is solved by the finite element method. Spatial-temporal distributions of the main components of the electromagnetic field are obtained. The ability to review the problem of deformation in the quasi-stationary formulation is justified. The distribution of the main component of the stress-strain state is presented. The influence of the current magnitude at the maximum stresses is evaluated

Nonlinear Dynamics of a Thin Plate in a Nonstationary Electromagnetic Field of the Inductor

The problems of the non-stationary deformation of a thin round plates in the electromagnetic field (EM-field) created by a massive inductor are considered. The finite element method is used for the analysis of spatial-temporal distribution of the electromagnetic field components and the parameters of the stress-strain state in the system of the «inductor-billet (plate)» with a consideration of the air layer. The data of measurements in experimental studies of vibrations of plates in pulsed EM-field are used to establish the frequency modes with the maximum values ponderomotive forces generated by an EM-field. The solution of the problem of plate vibrations was obtained. The temporal and spatial distribution of components of the electromagnetic field, displacements and stresses on the surface of the plate with the analytical solutions and experimental data are compared. Areas with the maximum displacements and stresses in the plate were installed for some «configuration» of electromagnetic fiel

FE-analysis of dynamic creep-damage in thin-walled structures

The models for description of creep-damage behaviour in materials and thin shallow shells and plates deforming in conditions of joint action of static and fast cyclic load are given. The properties of the proposed material model were established by comparison of experimental and numerical data. The method for numerical simulation by in-house code of a dynamic creep and long-term strength of shallow shells and plates is created on the basis of the FEM. New laws of dynamic creep influence on stress-strain state, shaping and fracture of thin-walled elements of structures had been established by numerical calculations. With the purpose of verification of the created method of dynamic creep numerical simulation of rectangular plates made of an aluminium alloy were carried in order to verify the method of calculation

Inelastic Deformation of Conductive Bodies in Electromagnetic Fields

Inelastic deformation of conductive bodies under the action of electromagnetic fields is analyzed. Governing equations for non-stationary electromagnetic field propagation and elastic-plastic deformation are presented. The variational principle of minimum of the total energy is applied to formulate the numerical solution procedure by the finite element method. With the proposed method, distributions of vector characteristics of the electromagnetic field and tensor characteristics of the deformation process are illustrated for the inductor-workpiece system within a realistic electro-magnetic forming process

Asymptotic Solution of Anisotropic Cyclic Creep Problem

Thin-walled structural elements made from rolled metal usually demonstrate anisotropic creep behavior. Very often the model of transversally-isotropic material is suitable for its description. Due to the difficulties in direct numerical integration the case of cyclic loading demands the development of suitable method of the creep problem’s solution when the material behavior isn’t isotropic. The general problem statement as well as the constitutive equations for two-dimensional creep problem are presented. Transversally-isotropic creep material model developed by O.Morachkovsky is used. The case of substantial stress values which are greater than yield limit is studied. Addition of cyclic loading, which is essentially varying the creep response, is analyzed. Deriving of resolving system of creep equations was performed by use of the method of asymptotic expansions jointly with the method of averaging in a period of stress cycle. This system allows simulation of only the problem of static loading with constitutive equations of special type, in which the values of cyclic parts of loading are included in so-called influence functions. These equations are derived from the general form by use of asymptotic expansions of creep strain functions with further averaging in a period of oscillations. Developed method is realized as an applied C+ + software. The Finite Element Method is used for solution of boundary-value problem jointly with Finite Difference Scheme for initial one. The results of experimental investigations of creep in specimens and plates with holes made from rolled steel are discussed. The anisotropic creep curves in three directions were obtained and constants for creep flow rule were determined. Additional number of experiments was performed for the case of cyclic loading. The comparison between experimental and numerical data shows the satisfactory agreement. Due to this a number of numerical examples for cyclic creep simulation in thin plates were performed and their results are discussed

Modeling of impact deformation processes of the ceramic container for radioactive waste storage

Results of researches in the field of designing containers for storage of radioactive materials are presented in the work. The purposes of researches include a development of an effective method of modeling static and dynamic deformation processes at shock impact on the ceramic container with radioactive materials at transportation. The next tasks have been solved: on the basis of the mathematical description of physic-mechanical processes of deformation of the complex design container has been chosen method of finite-element's for effective modeling of the stress-strain State of static and dynamic deformation processes in the containers made of ceramic elements; laws of deformation, estimations of durability and rigidity for designed containers have been received after calculations by means of the computer software; recommendations on perfection of a design of the container for maintenance of requirements to safety are given. Analysis Finite Element Method (FEM) has been conducted in the ANSYS system and results is presented

Розрахунки термодеформування систем електропровідних тіл під дією електромагнітного поля

Лавінський, Д. В. Розрахунки термодеформування систем електропровідних тіл під дією електромагнітного поля = Calculations of thermodeformation of systems of electroconductive bodies under the action of the electromagnetic field / Д. В. Лавінський, О. К. Морачковський // Зб. наук. пр. НУК. – Миколаїв : НУК, 2020. – № 2 (480). – С. 28–33.Анотація. Роботу присвячено питанням розрахункового аналізу деформування систем електропровідних тіл за дії електромагнітного поля. Дія електромагнітного поля проявляється в разі впливу на електропровідні тіла, у виникненні розподілених електромагнітних сил та розподілених джерел тепловиділення. Силова дія електромагнітного поля використовується у класі технологічних операцій – магнітно-імпульсній обробці матеріалів. Розробка та вдосконалення технологій магнітно-імпульсної обробки потребують проведення комплексних розрахункових досліджень, зокрема й спрямованих на оцінювання конструкційної міцності складових елементів. У роботі використовується метод розрахункового аналізу, який спирається на схеми методу скінчених елементів. Запропонований розрахунковий метод застосовано до аналізу розповсюдження електромагнітного та температурного поля, термодеформування прес-форми для гібридного (ізостатичного й електромагнітного) пресування порошків високоміцних сполук. Створено розрахункову схему, яка містить усі основні елементи прес-форми, а також зовнішній багатовитковий спіральний індуктор. Для врахування контактної взаємодії елементів прес-форми застосовується спосіб введення контактних шарів, які дискретизуються за допомогою відповідних спеціальних скінчених елементів. Одержано просторово-часові розподіли основних характеристик електромагнітного поля в елементах прес-форми. Характер розподілу електромагнітного поля під час імпульсу дозволяє застосовувати для аналізу термодеформування квазістаціонарний підхід відповідно до часового максимуму поля. Розв’язано також задачу нестаціонарного розповсюдження температурного поля завдяки ефектам тепловиділення. Аналіз термодеформування дозволив з’ясувати найбільш навантажені елементи прес-форми, порівняння з результатами розрахунків для випадку ізостатичного пресування дозволяє стверджувати, що в разі гібридної схеми навантаження прес-форми знижується, що дозволяє збільшувати тиски пресування. Одержані результати розрахунків дозволять сформулювати конкретні рекомендації щодо вибору раціональних конструкційних і експлуатаційних параметрів технологічної операції. Використані методи, підходи та розрахункова схема можуть застосовуватись до подібних технічних та технологічних систем зі спіральними багатовитковими індукторами.Abstract. The work is devoted to the issues of computational analysis of deformation of systems of electrically conductive bodies under the action of electromagnetic field. The action of the electromagnetic field is manifested, in the case of influence on electrically conductive bodies, in the occurrence of distributed electromagnetic forces and distributed sources of heat. The forces of the electromagnetic field are used in the class of technological operations – electromagnetic forming. Development and improvement of electromagnetic forming technologies require complex computational research, including those aimed at assessing the structural strength of components. The paper uses the method of computational analysis, which is based on the schemes of the finite element method. The proposed calculation method is applied to the analysis of electromagnetic and temperature field propagation, and thermodeformation of a press-mold for hybrid (isostatic and electromagnetic) compression of powders of high-strength compounds. A calculation scheme has been created, which contains all the main elements of the press-mold, as well as an external multi-turn spiral inductor. To take into account the contact interaction between the elements of the press-mold, a method of introducing contact layers is used, which are modeled using the appropriate special finite elements. The space-time distributions of the main characteristics of the electromagnetic field in the elements of the press-mold are obtained. The nature of the distribution of the electromagnetic field during the pulse allows to apply a quasi-stationary approach to the analysis of thermo-deformation in accordance with the time maximum of the field. The problem of non-stationary propagation of the temperature field due to the effects of heat release is also solved. The analysis of thermo-deformation allowed to find out the most loaded elements of the mold, comparison with the results of calculations for the case of isostatic pressing suggests that in the case of a hybrid scheme, the load of the mold is reduced, which increases the pressing pressure. The obtained results of calculations will allow to formulate specific recommendations on the choice of rational design and operational parameters of the technological operation. The methods, approaches and calculation scheme used can be applied to similar technical and technological systems with spiral multi-turn inductors

Дмитро Васильович Бреславський – видатний вчений – механік (до 60-річчя з дня народження)

The article contains an essay about the outstanding scientist - mechanic, doctor of technical sciences, professor Dmytro Vasylovych Breslavsky. A brief summary of the main scientific results obtained by D.V. Breslavsky in various branches of informatics and flight control, mechanics: the theory of creep, continuum mechanics of damage, the theory of plates and shells. The description of the scientific path of Dmytro Vasylovych Breslavsky from the student's bench to the scientific leadership of graduate students and doctoral students is given, as well as the path of the administrator, head of the Department and Faculty. Scientific achievements are presented in international cooperation with the Otto von Guericke Magdeburg University and the Martin Luther University in Halle, Germany, as well as cooperation with enterprises and institutions of Ukraine. A description of the applied research of devices, equipment, machines and structures is given. The article contains main scientific publications of Professor, Doctor of Technical Sciences Dmytro Vasylovych Breslavsky. He is the author of 200 scientific publications, co-author of four monographs, two textbooks. Research interests: physically nonlinear problems of mechanics of a deformable solid (creep, fracture under cyclic and impact loads), finite element method, computer modeling of technical processes, IT-technologies in problems of mechanics.The result of many years of work in the direction of creating a theory of dynamic and cyclic creep of materials and structural elements was provided in scientific reports D.V. Breslavsky and O.K. Morachkovsky, made at world scientific conferences in Belgrade and Montreal and published in scientific publications.У статті міститься нарис про видатного вченого – механіка, доктора технічних наук, професора Дмитра Васильовича Бреславського. Надано коротке викладення основних наукових результатів, що їх отримано Д.В. Бреславським у різних розділах інформатики та керування польотами, механіки: теорії повзучості, континуальній механіці пошкоджуваності, теорії пластин та оболонок. Наведено опис виконаних прикладних досліджень приладів, техніки, машин та конструкцій